肱骨（拉丁语：Humerus）是人类和一些脊椎动物的上肢骨骼之一。

肱骨上方为肱骨头（Caput humeri），它与肩胛骨共同构成肩关节。肱骨头有两骨性突起，被称为大小结节（Tuberculum majus und minus）。大结节（Tuberculum majus）上有棘上肌（Musculus supraspinatus），棘下肌（Musculus infraspinatus）和小圆肌（Musculus teres minor）依着。小结节（Tuberculum minus）则标示着胸大肌和肩胛下肌（Musculus subscapularis）。两个结节之间有一沟，结节间沟（Sulcus intertubercularis），有肱二头肌的长头肌腱通过。而在结节间沟中还有一突起，被称为中结节（Tuberculum intermedium）。

The humerus (/ˈhjuːmərəs/, Plural: humeri) is a long bone in the arm or forelimb that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The upper extremity consists of a rounded head, a narrow neck, and two short processes (tubercles, sometimes called tuberosities). Its body is cylindrical in its upper portion, and more prismatic below. The lower extremity consists of 2 epicondyles, 2 processes (trochlea & capitulum), and 3 fossae (radial fossa, coronoid fossa, and olecranon fossa). As well as its true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to commonly get fractured, thus often becoming the focus of surgeons.